U.S. patent number 5,083,778 [Application Number 07/544,753] was granted by the patent office on 1992-01-28 for golf club putter head.
Invention is credited to Michael B. Douglass.
United States Patent |
5,083,778 |
Douglass |
January 28, 1992 |
Golf club putter head
Abstract
A golf putter having a novel putter head is disclosed. The
putter head includes a body of generally rigid material and a
resilient laminated striking face which is secured to a club face
undersurface defined by the putter head body. The laminated
striking face includes at least an outer layer of resilient
material having an outer surface for striking a golf ball and an
inner layer of resilient material which is secured against the club
face undersurface and which has a hardness which is less than that
of the outer layer. The resilient outer layer preferably has a
hardness which is equal to or greater than the hardness of a golf
ball which is generally greater than about 90 durometers A.
Inventors: |
Douglass; Michael B.
(Wheatridge, CO) |
Family
ID: |
26854071 |
Appl.
No.: |
07/544,753 |
Filed: |
June 27, 1990 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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157373 |
Feb 18, 1988 |
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Current U.S.
Class: |
473/329;
273/DIG.10 |
Current CPC
Class: |
A63B
53/0487 (20130101); Y10S 273/10 (20130101); A63B
53/0425 (20200801); A63B 53/0416 (20200801) |
Current International
Class: |
A63B
53/04 (20060101); A63B 053/04 () |
Field of
Search: |
;273/167-175,77R,DIG.3,DIG.6,DIG.4,DIG.12,DIG.22,DIG.29,186D,DIG.10 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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6060576 |
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Mar 1987 |
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JP |
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23691 |
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1907 |
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GB |
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20961 |
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1908 |
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GB |
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2003 |
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1914 |
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GB |
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1405194 |
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Sep 1975 |
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GB |
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2124910 |
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Feb 1984 |
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GB |
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2173407 |
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Oct 1986 |
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GB |
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Primary Examiner: Grieb; William H.
Assistant Examiner: Passaniti; Sebastiano
Attorney, Agent or Firm: Hanes; Richard W.
Parent Case Text
This is a continuation-in-part of application Ser. No. 07/157,373
filed 2/18/88, to the same inventor, now abandoned.
Claims
What is claimed:
1. A golf putter comprising:
a club shaft having a gripping portion at one end of said
shaft;
a putter head attached to the other end of said shaft, said putter
head including a body defining a club face undersurface and a
yieldable laminated striking face secured to said body against said
undersurface, said laminated striking face comprising an outer
resilient layer, an inner resilient layer, and an intermediate
layer between said inner and outer layers, said laminated striking
face being yieldable to absorb energy when struck by a ball so as
to achieve controlled dampening of the struck ball, said
intermediate layer being viscous to enable said inner and said
outer resilient layers to move laterally relative to one another
when said outer resilient layer is struck, whereby the viscous
layer absorbs shear forces associated with said struck ball.
Description
BACKGROUND OF THE INVENTION
This invention relates to golf clubs and more particularly to the
putter head of a putter type club.
A golfer's desire for a putter providing improved putting accuracy
and control is well documented by the number of patents directed to
putter type clubs. Some of the more recently issued patents in this
area disclose putters having striking faces which are made from a
different, generally more resilient, material than the body of the
putter head itself which is typically made from a metal such as
brass, steel or aluminum or some other relatively rigid material
such as a graphite or ceramic composite.
One of the earliest known putters having a striking face made from
a resilient material is disclosed in U.S. Pat. No. 3,211,455 to
Hyden. The resilient material in Hyden is preferably a rubber
having a hardness between about 65 and 85 durometers. The resilient
striking face is stated to provide the golfer with a greater sense
of touch or feel during stroking of the ball, especially on a
putting green.
U.S. Pat. No. 3,218,072 to Burr discloses golf club heads utilizing
prestressed porous carbon inserts to form the striking faces.
Porous carbon's resiliency is stated to make it possible to
increase the rebound of a golf ball from the striking face of the
club when the ball is struck with the club, thereby increasing the
distance that the golf ball can be driven. The compressibility and
elasticity of porous carbon is also disclosed as making it possible
to firmly secure the insert in the club head without having to use
adhesives, screws or other attaching means.
U.S. Pat. No. 4,156,526 to Huggins et al. discloses a putter having
a putter head which defines an elongate cavity in which a resilient
block is disposed which serves as the putter striking face. The
size and shape of the block is such that when striking a golf ball,
the rearwardly deformed area of the block assumes an elliptical
shape which moves in vertical direction relative to the golf ball
when the deformed area returns to its initial configuration. This
vertical movement of the block is disclosed as having no tendency
to divert the golf ball from a path normal to the putter striking
surface. As such, putting accuracy is apparently maintained.
U.S. Pat. No. 4,199,144 to Skelly discloses a putter having a
striking face made of rock hard plastic. The rock hard plastic is
said to deliver a stronger force against the golf ball than the
putter face of a conventional putter so that the ball will travel
approximately 4 to 8 inches farther than conventionally
expected.
U.S. Pat. No. 4,422,638 to Tucker discloses a golf putter having a
soft face formed from an elastomer having high resiliency and a
hardness greater than about 70 durometer A and preferably less than
the hardness of a golf ball which is stated to be in the range of
99 durometer A and 50 durometer D at the surface of the ball. The
high resiliency of the elastomer is believed to cause the ball to
rebound sharply without energy loss, thereby increasing the
distance of ball travel. This, in turn, permits utilization of a
shorter back swing which is stated to substantially increase
accuracy of the back swing and, thus, the direction of ball
travel.
U.S. Pat. No. 4,679,792 to Straza et al., discloses a golf putter
head having a striking face insert which comprises a honeycomb
cellular structure. The honeycomb cells are filled with a
resilient, epoxy material to increase momentum imported to a golf
ball upon impact. The exposed edges of the honeycomb cells which
contact the ball on impact are stated to prevent slippage and
enhance directional control over the ball line of travel.
The use of ceramics as a face plate for a golf club is well known.
Such is shown in U.S. Pat. No. 3,975,023 to Inamori. Such ceramic
face plates are designed to be extremely non-yielding (note FIG.
7), and are capable of increasing the flying distance of the ball.
Thus, an appreciable dampening effect is not achieved.
Similarly, metal face plates even when backed with higher
elasticity material, as shown in Japanese Document No. 2060-576 to
Nagasaki et al. are used to obtain "good batting condition."
Dampening of the rebound of the struck ball and energy absorbing
features are not discussed.
The use of laminated layers for golf clubs is well known as shown
by U.S. Pat. No. 4,204,684 to Molitor. Such laminations, however,
are arranged generally parallel with the sole or lower surface of
the club. The laminated layers do not form only the striking face
secured to a golf club body. In fact, the construction of Molitor
renders "unnecessary the use of a sole plate or an insert or face
piece in the impact face of the head" (column 2), and thus teaches
away from such a use.
While there can be no doubt that the aforedescribed putters and
clubs have satiated many a golfer, at least psychologically, the
thirst of many a golfer for a new and improved putter or club
remains unquenched.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a putter which
dampens or reduces rebound of the golf ball from the striking face
of the putter to increase control over the ball's line of travel
and distance of travel, thereby increasing putting accuracy.
Another object of the present invention is to provide a putter
having a larger sweet spot which provides the golfer which a
greater sense of touch and feel when making a putt, thereby
increasing putting accuracy.
Yet another object of the present invention is to provide a putter
which decreases surface contact of the golf ball with the striking
face of the putter to increase control over the golf ball's line of
travel, thereby increasing putting accuracy.
A further object of the present invention is to provide a putter
which increases the length of the golfer's backstroke during
putting to increase putting accuracy, particularly when making
short putts of less than about six feet.
Another object of the instant invention is to provide a putter or
golf club which will absorb shear forces generated during
deflection of a yielding face plate when a ball is struck. Such a
struck ball will then tend to rebound in a direction more
perpendicular to the face of the club or putter in a dampened
manner.
In accordance with these objectives, the present invention provides
a golf club head including a body defining a club face undersurface
and a laminated golf ball striking face which is secured to the
body against the body's undersurface. The laminated striking face
includes at least an outer resilient layer and an inner resilient
layer. The other layer defines a surface for striking a golf ball.
the inner layer is secured against the body's undersurface and has
a hardness which is less than that of the outer layer. A third
viscous layer could also be provided between the outer and inner
layers.
In a preferred embodiment, the outer layer has a hardness which is
equal to or greater than the hardness of a golf ball which is
generally at least about 90 durometers A. The inner layer is
preferably made from a softer material having a hardness between
about 35 and 90 durometers A. The body of the golf club head is
preferably made from a relatively rigid material such as a metal, a
ceramic composite or a graphite composite. The club face
undersurface is preferably recessed in a cavity defined by the club
head body and the laminated striking face is preferably in the form
of an insert which is mounted in the cavity so that the outer
surface of the insert's outer layer is contiguous and flush with an
outer front surface defined by the club head body. The cavity and
insert also preferably include dove-tail shaped portions which
matingly engage each other to mechanically secure the insert in the
cavity against the body's undersurface.
The present invention also provides a golf putter including a club
shaft having a gripping portion at one end of the shaft and a
putter head attached to the other end of the shaft. The putter head
includes a body defining a club face undersurface and a laminated
striking face which is secured to the putter head's body against
the undersurface. The laminated striking face includes at least an
outer layer of resilient material having an outer surface for
striking a golf ball, an inner layer of resilient material which is
secured against the putter head body's undersurface. An
intermediate viscous layer could also be provided between said
inner and outer layers. The inner layer has a hardness which is
less than that of the outer layer.
The present invention also provides a golf ball striking face for a
putter head which includes a laminate having at least an outer
layer of resilient material for striking the surface of a golf ball
and an inner layer of resilient material for attachment to a
surface of the putter head. An intermediate viscous layer could
also be provided between said inner and outer layers. The inner
layer has a hardness which is less than that of the outer
layer.
Additional advantages of this invention will become apparent from
the description which follows, taken in conjunction with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top cross-sectional view of a prior art putter head
which illustrates the surface contact made between an elastomeric
striking face insert of the putter head and a golf ball which is
being struck by the putter head.
FIG. 2 is a side view of a putter of the present invention.
FIG. 3 is a perspective view of a putter head of the present
invention.
FIG. 4 is a cross-sectional view taken along lines 4--4 of FIG.
3.
FIG. 5 is a cross-sectional view taken along lines 5--5 of FIG.
3.
FIG. 6 is a cross-sectional view similar to that illustrated in
FIG. 3 showing the deformation which takes place in a laminated
striking face insert of the present invention when striking a golf
ball.
FIG. 7 is a cross-sectional view similar to FIG. 4 showing a
laminated striking face having three layers.
FIG. 8 is an enlarged section of the cross-section of FIG. 7.
FIG. 9 is a graph showing the relationship between the striking
force of a golf ball on a putter and club and the absorption of
shear forces in the movement of the face plate.
FIG. 10 is a graph showing the energy absorbed by the movement of
layers of the laminated face plate of the instant invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 illustrates a golf ball 1 being struck by a putter head 2 of
a conventional putter (not shown). The putter head has an
elastomeric, single layer, striking face insert 3 which defines a
golf ball striking surface 4. Insert 3 is mounted in and secured to
a cavity 5 defined by a metallic body 6 of the putter head.
As illustrated in FIG. 1, insert 3 undergoes substantial
deformation when it makes contact with the golf ball. As such,
there is substantial surface contact between striking surface 4 of
insert 3 and the surface of the golf ball. Such surface contact is
undesirable in that it apparently causes the golf ball to
erratically rebound from the striking surface of the insert.
This problem is discussed in U.S. Pat. No. 4,156,526 to Huggins et
al. wherein it is disclosed that erratic rebounding (or lateral
deflection of the golf ball) can be avoided with an elastomeric
striking surface which deforms elliptically when struck. The
elliptical deformation is stated to cause the golf ball to rebound
in a direction which is normal to the striking surface of the ball.
As such, lateral deflection or erratic rebounding of the ball is
apparently avoided.
While Huggins provides a solution to erratic rebounding, it is
believed that the problem can also be solved or at least greatly
minimized by reducing the extent of surface contact between the
striking surface of the putter head and the surface of the golf
ball. With less surface contact (i.e., more point-like contact),
fewer and less powerful laterally directed rebounding forces should
contact the golf ball. Accordingly, the golf ball should rebound in
a direction normal to the striking surface of the putter head,
thereby solving the problem of erratic rebounding.
FIGS. 2 through 6 illustrate a preferred embodiment of a putter
head 10 of the present invention which has as an object, among
others, the minimization of surface contact between the striking
surface of the putter head and the surface of the golf ball.
FIG. 2 illustrates a putter 12 having a shaft 14 with putter head
10 attached to one end of the shaft and a gripping portion 16
attached to the shaft's other end. The putter head and gripping
portion 16 are preferably attached to shaft 14 with an adhesive
such as glue. Other attaching means known to those skilled in the
art may also be employed and such are considered to be within the
purview of the present invention.
As best illustrated in FIGS. 3 through 5, putter head 10 generally
includes a body 18 (preferably made of a rigid material such as a
metal, a graphite composite or a ceramic composite) and a laminated
club striking face insert 20.
Insert 20 is mounted in a cavity (not numbered) of body 18 which is
defined by an undersurface 22 and a beveled or dove-tail shaped
portion or wall 24. The insert is mechanically secured to the body
against undersurface 22 by providing the insert with a beveled or
dove-tail shaped edge or portion 26 which matingly engages with
dove-tail shaped wall 24. While not illustrated, adhesives and
other known attaching means may be employed within the spirit of
the present invention to secure the insert to undersurface 22.
Insert 20 is also sized and configured to define a planar striking
surface 28 which, as best illustrated in FIGS. 3 through 5, is
contiguous, coplanar and flush with a generally planar front body
surface 30 defined by body 18.
Laminated insert 20 also includes at least two resilient layers; an
outer resilient layer 32 and an inner resilient layer 34. The outer
resilient layer in accordance with an important aspect of the
present invention has a hardness which is greater than that of
inner layer 34. In a preferred embodiment, the outer layer has a
hardness greater than that of a conventional golf ball which is
about 90 durometers as measured by the Shore A test.
It is also preferred that the outer layer have a hardness which is
less than 110 durometers A. A resilient, thermoplastic polymer
having a hardness which is suitable for use as outer layer 32 is an
ionomer resin made and sold by the Du Pont Company of Wilmington,
Del. under the trade name Surlyn 8660. Surlyn 8660 has a hardness
of 62 durometers Shore D which is equal to about 98 durometers on
the Shore A scale. The Du Pont Company also makes other Surlyn
ionomer resins which may be suitable for use as outer layer 32.
Surlyn is a registered trademark of the Du Pont Company. The
thickness of the outer layer ranges from 0.05 inches to 0.35
inches.
Resilient inner layer 34 having a hardness less than that of the
outer layer is preferably made from an elastomeric material such as
rubber. Inner layer 34 may also be made from soft Surlyn ionomer
resins such as Surlyn 9450 which has a hardness, Shore D, of 54
durometers. The thickness of the inner layer ranges from 0.05
inches to 0.35 inches.
FIG. 6 illustrates the deformation believed to take place in insert
20 when a golf ball 36 is struck by a golfer utilizing the putter
of the present invention. As illustrated, outer layer 32 bends or
yields inwardly without compressing to any substantial extent while
inner layer 34 distorts significantly. Since outer surface 34 bends
or yields inwardly rather than compressing significantly (which is
what happens to the single layer insert illustrated in FIG. 1)
surface contact between the golf ball and the outer layer striking
surface 28 is greatly reduced. This can be easily visualized by
comparing the surface contact which takes place between ball 36 and
surface 28 in FIG. 6 with the surface contact taking place between
golf ball 1 and striking surface 4 of insert 3 illustrated in FIG.
1. As can be seen, there is much less surface contact with the ball
in FIG. 6 than there is in FIG. 1. Accordingly, golf balls struck
with the putter head of the present invention illustrated in FIG. 6
should experience much less erratic rebounding than those struck
with that illustrated in FIG. 1. As such, a golfer's ability to
maintain control over the ball's line of travel should be greatly
enhanced with the putter of the present invention. Thus, putting
accuracy should be greatly improved.
The deformation which takes place in insert 20 as illustrated in
FIG. 6 also slightly dampens or reduces rebound of the ball. Such
dampening occurs because outer layer 32 bends across almost its
entire length which, in turn, distributes the ball's energy of
impact over a wider area across inner layer 34. Accordingly, with
more surface area available for energy absorption, inner layer 34
is capable of absorbing more energy than an insert consisting of a
single layer of material such as that illustrated in FIG. 1 wherein
deformation (and thus energy absorption) is more localized.
A further embodiment of the invention is illustrated in FIGS. 7 and
8. In this embodiment, the two laminated layers 32 and 34 are
secured together using a suitable viscous or tacky adhesive 40 also
known as transfer adhesive. This forms a very thin third layer in
the laminated insert structure.
As illustrated in FIG. 8, the layer 40 is capable of movement
relative to layers 34 and 32 and thus is energy absorbing. Assuming
the outer layer 32 is struck and moves in a direction indicated by
arrow 41, the transfer adhesive 40 applies opposing forces in the
direction of the arrows 42. Inner layer 34 responds with movement
in the direction of arrow 43. The viscous nature of the adhesive
layer 40 allows layers 34 and 32 to move relative to each other.
Thus the viscous layer 40 absorbs energy in the relative movements
of the layers and such energy is given off as heat. This energy
absorption dampens the rebound of the ball. Shear forces will be
absorbed by the relative movements of the laminated layers. Thus,
the ball will tend to rebound in a direction more perpendicular to
the striking face in a dampened manner.
FIG. 9 shows a graph depicting the relationship of the force of the
ball struck on the outer face plate to the absorption of the shear
forces. As shown in the graph at 50, the absorption of shear forces
increases proportionally to the force of the ball.
FIG. 10 shows a graph of the movement of the outer face plate as a
function of the force of the ball. The straight line on the graph
represents the force of the ball on the face plate and the
resulting deflection of the face plate. The curving line shows the
return movement of the face plate from its deflected condition and
the reduced force applied to the ball during its rebound. The
shaded area 51 bounded by these graphs represents the mechanical
energy absorbed from shear strain in the viscous transfer adhesive
layer 40. The energy absorption feature of the instant invention
results in a dampening or reduction in ball rebound. Such dampening
(or reduction in ball rebound) also apparently causes the ball to
remain on striking surface 28 of the outer layer for a fraction of
a second longer than it does when striking a surface having high
rebound characteristics such as that illustrated in U.S. Pat. No.
4,422,638 to Tucker. This is advantageous since it gives the golfer
the feeling of having a larger sweet spot on the striking surface
of the putter head. Dampening also enhances putting accuracy by
providing the golfer with the feel of actually "pushing" the ball
to the hole.
Dampening of ball rebound also permits utilization of a longer
backstroke which, despite claims to the contrary, enhances putting
accuracy, particularly when making short putts of less than about
six feet. Contrary to popular belief, most short putts are missed,
not because the golfer chokes, but rather because the golfer's
backstroke is not long enough to enable him to accurately align the
striking face of the putter head with the desired line of ball
travel. A longer backstroke also makes it easier for the golfer to
control the amount of force delivered to the ball when making the
putt, thereby enhancing the golfer's ability to control the
distance the ball travels.
This invention has been described in detail with reference to a
particular embodiment, but it will be understood that various other
modifications can be effected within the spirit and scope of this
invention.
* * * * *